The present invention pertains to compounds containing a lactam group in combination with a substituted 4-piperidinyl hindered amine moiety which are useful as light and heat stabilizers for organic materials and to stabilized compositions containing said compounds.
The hindered amine compounds having the 2,2,6,6,-tetrasubstituted piperidinyl structure have long been known as effective light stabilizers for organic materials and have enjoyed considerable commercial success.
Such hindered amine light stabilizers are described in detail by H. J. Heller and H. R. Blattmann, Pure and Applied Chemistry, 36, 141-161 (1973).
It is known from U.S. Pat. Nos. 3,850,877 and 4,033,928 that esters and amides of substituted 2,2,6,6-tetramethylpiperidine are good light stabilizers for polymeric substrates, particularly polyolefins and epoxy resins.
U.S. Pat. No. 4,309,546 describes substituted N-piperidin-4'-yl-2-pyrrolidone-4-carboxylic acid derivatives of formula ##STR1## where n is 1-4, R.sub.1 is hydroxyl, alkoxy, amino or substituted amino, X is a direct bond or linking group and Pip is substituted or unsubstituted 2,2,6,6-tetraalkylpiperidn-4-yl. These compounds are useful as light stabilizers.
Although structurally the instant compounds are somewhat related to the compounds of U.S. Pat. No. 4,309,546, the instant compounds possess better solubility characteristics, and exhibit superior thermal and particularly superior hydrolytic stability compared to said compounds.